1. Field of the Invention
This invention relates to an adjustable unitized shipping container for frangible sheet-like units and, more particularly, to a reusable container for shipping, storing and unloading large multiple glazed window units.
2. Discussion of the Technical Problems
The emergence of large scale steel construction of office buildings has made possible a constantly increasing size of window surfaces at the same time that the reduced ambient light available in the city environment has increased the demand for more window surface area. These large window surfaces have, however, presented problems in energy transmission such as controlling heat loss in winter, heat gain in summer and insulating against noise while still increasing the amount of light transmitted through the window. To meet those problems, the large glass surfaces employed are generally double glazed with a separating air space between the two sheets of glass.
With the size of the modern double glazed window units increasing, the difficulty of handling the units is also increasing. The units are often as large as 108 inch.times.60 inch (274.3 cm.times.152.4 cm) and larger. The units typically weigh up to 275 lb. (124.7 kg). Representative of the types of multiple glazed units used in large commercial construction projects include the multiple glazed units as disclosed in U.S. Pat. No. 3,919,023 and U.S. Pat. No. 4,109,431. The multiple glazed units are usually fabricated at a manufacturing facility and shipped to the jobsite.
Once the previously fabricated large multiple glazed units arrive at the site for installation they must also be raised to the floor on which they will be installed. The units may also need to be stored at the site. A conventional container for shipping and storing the units is often a simple wooden crate with suitable bracing and support for the glass. These expendable wood containers are bulky and quite heavy. They also create a disposal problem after use.
During the construction of a building, it is often necessary to provide outside access on each floor for loading and unloading building material using a crane or hoist. This access is often provided by leaving exterior sections unglazed. The sections are later closed by installing the glass. Accordingly, it is necessary to store some multiple glazed units of varying sizes on different floors for later installation. Since storage of some sizes may involve many months, it is necessary that the multiple glazed units be stored in a manner so that they would not become easily broken and yet would be readily available for easy handling and installation when required. Storage space during construction is at premium and the storage container should be designed so as to conserve space.
Since the sizes of multiple glazed units utilized on any given construction job vary considerably with many sizes being utilized at one job site, it is also necessary that the container be the correct size for the multiple glazed unit or be adjustable to the different sizes.
Once the shipping container for the mulitple glazed unit is placed on the floor it must be capable of easy movement. Due to the large size of the multiple glazed unit, typically loaded shipping containers weight upward of 4000 pounds (1814.4 Kg). The containers therefore should be capable of being easily moved with a fork truck, hand lift dollies or by some other method.
As previously mentioned it is the practice in large commercial construction to utilize one or more cranes for lifting building material, such as the multiple glazed window units, from the ground surface up to the floor where they will be utilized. Many types of building materials compete for the scant crane time available. It would be advantageous, therefore, for any multiple glazed unit shipping container to provide a structure which would allow for easy crane attachment and disengagement.
Once the shipping container is placed on the floor and the glass is to be unpacked, the container should be capable of easy unloading and a minimum of waste material should be generated by unpacking and unloading the glass. The empty containers should also not take up much space.
Given the problems discussed above, it would be advantageous to provide a returnable steel shipping container for shipping multiple glazed units to building construction locations. The container should be adjustable to accommodate various glass lengths and widths and the container should be crane hoistable and easily unpacked. It should also be capable of easy movement upon the floor location. The container should provide adequate interim storage for units not yet installed, and the container should not be burdensome to remove from the building site. The instant invention is directed to those needs.